The String Cheese Theory
by JustSomePinecest
Summary: Pinecest oh yah. The best trash ship. You guys know me by now. Cowritten or roleplayed.. *grins* by my wonderful Dipper, Smilefundip on tumblr. I enjoyed it I hope you guys do too! Nsfw and all that fun stuff. Written from Dip's POV mostly.


Dipper was a little upset.

It had been a few days since he'd had any action from Mabel and being a 17 year old, hormonal teenage boy made him well.. let's say a little high and dry after four days of nothing.

Their father wouldn't be home for another three hours and there he sat on one of the bar stools, drumming his fingers on the countertop of the kitchen island, grinding his teeth and staring at the wall, trying to distract himself. Images of his and his sister's latest tryst playing over and over in his head on loop like it had been doing for the last two days.

He was really, really angry and hating advanced biology right about now. Mabel had finally gotten serious about her classes at about the worst time for him. He bounced his knee for a minute or two before getting up and going to the fridge, his mouth twisted into a mix of boredom and frustration. He pulled out a piece of string cheese and sat back hard on the bar stool with a sigh, tearing open the plastic and peeling the piece of cheese apart slowly and nibbling on it; the tedium of the activity satisfying him if only slightly as he tried not to think of Mabel anymore. Even though that was impossible.

His ears pricked up as he heard the squeak of footsteps on the stairs. Mabel came down the stairs wearing those damn little shorts she always did when she was doing her homework.. Or watching a movie.. or really doing anything with him when their parents weren't around. Those dumb little too-small shorts with the lame little hot pink flame pattern on them. A too small shirt hid her still growing and.. rather large breasts, hiding them from him. He could swear she was wearing that shirt on purpose. He knew she wore the shorts on purpose. Since she'd only started wearing them after they got 'too close' as he like to put it.

She was smiling. God dammit. It was that special little smile. He knew she was trying to tease him and oh god was it ever working. He smiled back tightly, trying not to let her get to him. He knew she'd just come down to get something to snack on then it was back to doing research and reading. Dumb DNA project.

He felt a little surprised as she walked over to him, still smiling. He gulped. Not having been this close to her in a few days was dramatically affecting him. She hadn't showered yet today, she smelled slightly of sweat. He felt a twitch from below and told his dick to promptly 'shut up' in his head. Outwardly he smiled.

"Can I have some?" She was grinning again. Jesus. Her smile was so pretty now that she'd had her braces off. Was she wearing lip gloss?

"Oh s-sure." He tried to keep his voice calm as he tore the remaining piece in half and went to hand it to her.

To his further surprise though she opened her mouth and he blushed. She wanted him to feed her. Why was she doing this? Why did she have to do this kind of stuff to him? He felt his armpits prickle with nervous itching as he peeled of a small, delicate string and moved it toward her waiting mouth.

She took it slowly and gently from his fingers, her eyes closing as her lips brushed against his fingertips.

Dipper kept his breath from coming out in a shudder as he felt her sticky lips against his sensitive fingertips. Yeah, lip gloss.

"M-mabel, cmon. Don't you have to finish your project?" He felt himself begin to sweat at the smile on her face.

She simply pointed to her open mouth. "Ah, ah!" She said. Indicating she was still hungry.

With a nervous swallow he pulled another small piece of cheese from the stick and hastily stuck it in her mouth, trying to pull his fingers away more quickly.

"H-hah!" He felt her warm, soft mouth around his fingers, sudden and hot. His mouth falls open. "Oh.. Fuck.." He could feel himself rising, tenting up in his pants almost immediately. He gritted his teeth and cursed his sensitivity.

"Your.. project.." He grunted.

She released his finger, staring into his eyes, her own heavily lidded. "Pff screw that dumb thing. I'll get back to it later." She went back to sucking gently at his finger, her tongue swirling against his fingertip.

"Hh-hh.. Ahh.. Oh.." Dipper felt his eyelids becoming heavy, watching hers as they drew him in. He was transfixed, the corners of his mouth twitching. "M-mabel.. Mabel.." He shuddered, his finger tingling. The feeling spread through his body, making him feel numb with pleasure.. well except for a few key parts. His cock was now pushed hard against the fabric of his jeans, making him grit his teeth again.

Without warning, Mabel slid her mouth down the rest of his finger, sucking suddenly hard, rubbing and wriggling her tongue along the underside, gazing into his eyes. Her eyes were smiling at him, laughing even.

He caught the look in her eyes, his eyebrows knitting together as his breath caught in his throat, his own fluttering closed; mouth open in a silent moan, a shuddering breath escaping. She had him again. He was paralyzed. He bit his lip, groaning deep in his throat as beads of sweat formed on his temple, glad he was sitting as his legs suddenly felt like jelly, falling open as his hips pushed forward with a mind of their own.

He opened his eyes as he felt her mouth leave his finger and her hand press into his pulling him to his feet. He stumbled awkwardly and followed her like some kind of cattle as she led him to the old couch.

He fell back as she pushed him square in the chest, his legs spreading again automatically. He let out another moan as her mouth latched onto his finger again. He looked at her, his eyes half open, clouded with lust as he looked deeply into her eyes, his mouth opening to speak again. "Fuck.. mmmm… you are.. you're driving me crazy.." His hips pressed upward as a damp spot slowly began to bloom in his jeans. He let out another groan as he felt himself tense up, squeezing another drop of warmth from his tip. He was getting even harder, it was starting to hurt, that's how hard he was.

He let out a sigh of almost relief as Mabel pulled his finger slowly from her mouth, a string of spittle leading from her lips to his fingertip. Simultaneously she leaned down and forward, firmly placing her hand on his throbbing crotch as she did. Her eyes closed as she kissed him deeply and passionately.

His gaze focused on the tantalizing bit of her wonderful saliva causing him to let off a soft, wavering moan. He licked his lips subconsciously, wanting to taste her mouth. He closed his eyes then, the heat of her wonderfully soft hand on his crotch made his hips arch in anticipation and pleasure. He felt the closeness of her face. His lips accepted her with tenderness, adding vigor with each passing moment, the kiss indeed searing and passionate. He raised his shaking hands to brush and caress her warm cheeks.

Next thing he knew, she was pressing her tongue past his lips, his own eagerly meeting hers, slipping and twisting against it. He felt her palm massage his crotch rhythmically. It was like magic. Pressing with just the right pressure on his too-swollen member. He didn't think it was possible to get harder. His hips jerked a couple of more times before settling as he felt her slide on his lap, leaving plenty of room for her hand between his legs.

He caressed her cheeks with care and affection before letting them fall gently, slowly reaching down to tug off those evil little shorts before planting his hands against her inner thighs, massaging his fingers against them. He was now grinding into her hand, trying so hard to keep rhythm.

Mabel wasn't wasting any time. He felt her quickly undo his button and zipper to get straight to his cock, briefly shaken from his hypnosis, his eyes wide. God damn. He smirked inwardly. He guessed maybe the four days had not been as easy for her as he previously thought. He made a mental note to remember that. That thought was blasted away though by the feeling of her pressing his jeans past his hips, her little hand reaching in to pull out his throbbing length from the split in his boxers. Christ her hand was warm.

That was when he felt her thumb press and rub against his sensitive head. He moaned loudly, her mouth muffling the sound. He bucked his hips into her hand as he felt himself tense up again, more precum secreting from his slit as she rubbed. Shhhit.. She was suckling on his tongue now with enough intent to make him explode right there and then. It made his eyes roll back in his head, his whimpering cries of pleasure ringing again into her mouth. He was completely hers. Putty, weak to her. His shaking hands moved from her inner thighs around to the back of them, squeezing softly just below her bottom, massaging her flesh. He groaned again, long and deep as his eyes closed tightly, feeling her hand cradle his cock now, squeezing, her slender fingers making his brain explode. Thoughts of wanting to ravage her now surfacing.

The sound of her sucking his tongue made him shudder afresh with pleasure and he could feel saliva threaten to drip down his chin. The thought of their fluids mixing made him feel so dirty yet so good. Her teeth scraped against his tongue, obliterating all thought again for a moment. It made him moan her name into her mouth and his eyes roll back in his head again. And now she was, touching him. Her soft hand moving on his throbbing cock so gently. And where he was cupping her bottom he could feel her moving slightly, rhythmically. Was this really doing that much for her? He wanted to make her feel good too. It wasn't right that he was feeling this way without her. One of his hands reaches back around her front, slipping down, drawing her panties aside and twisting them so he could press his index and middle finger on each side of her clit, beginning to gently massage her there, other hand cupping her bottom, giving it a squeeze.

Mabel felt the slickness of more precum as she squeezed and stroked him, hearing him pant and groan as it beaded up around his slit and dripped down his head to her waiting grip. The warmth and throbbing and just sheer hardness of him made her almost dizzy with pleasure as she slurped against his mouth, a bit of saliva finally drooling down her chin as she sucked and snipped at his tongue, feeling it writhe and twitch, recognizing something like her name being moaned.

He felt her hips press forward of their own accord as his strong fingers pulled and stroked at her clit, and she rewarded him with a loud groan, feeling a little proud of himself when her strokes faltered slightly.

His cock gave a painful throb, longing to be inside of her, not knowing he could produce this much fluid. He felt a bit like a faucet. This is what he got for not masturbating for those four days. He did know however that all that slickness was making her soft little hands feel incredible against him. With a very contented groan he pressed more firmly against her wet flesh, letting his slender fingers press harder together, grasping her clit between them, moving them up and down rhythmically. He could barely speak now, words failing him utterly. Only deep groaning and strangled cries could be heard coming from him.

Mabel moved her hips more dramatically along with his as she stroked and rubbed him mercilessly, her thumb coming up to slide against that spot right under his head that made his whole body tingle. She knew it was his favorite spot. She moved her hips in unison with his, with their movements. She only faltered every now and then from the intense pleasure. She gave a rough bite at his tongue every time she felt a hot throb from below, each throb, each bite bringing her closer to climax.

He whined softly, that weird little whimper he had when he was a kid as he felt her thumb sliding over his favorite most tender spot, his hips giving a particularly hard jerk. He lost his pace, erratically moving his hips against her hand, knowing he was close. He was going to cum, he knew it. Feeling shivers ripple down his body, he felt the heat boil over in his belly, spreading throughout him, his blood pumping hard, racing in his chest. There was a throbbing down below, the fire spreading throughout his body. Everything was just too much for him to handle.

His hand falters for just a moment before releasing her little nub from between his fingers. His fingertips slide down her slick inner walls, pushing his fingers as deep as they could go, drawing them out only to thrust them back in again. His long fingers pressing up against her gspot, dragging them against it. He stroked in and out, his fingers constantly, relentlessly hitting it, his palm slapping softly against her clit, grinding each time into with each smooth stroke of his hand. He wanted to please her the best way he knew how. His brain was having trouble working though and he was teetering so close the edge. He knew he would fall and he wanted her to go with him.

She felt his hips give a jerk and grinned into his lips, knowing she had him right where she wanted him. He was close just like she was and she knew it. But she began to lose all sense of pacing and concentration as she felt his long, nimble fingers slip into her. How could a boy, who had been a virgin a few months ago and been so clumsy just a few years ago, have such control over his fingers like this? She blamed the piano and guitar lessons and almost cursed and blessed them in the same breath as she felt his fingers flutter against her most tender, sensitive spot, sending sparks of confusion and hazy pleasure through her mind and body. She bit at his tongue again and groaned, trying desperately to keep in time with him, her hand squeezing harder and moving suddenly much faster. She was trying to tell him she was ready.

Dipper felt her hips buck and roll as she breathed hard and fast, groaning into his mouth, squeezing her eyes shut tight as she stilled her movements except for a few hard thrusts against his hand. He took the opportunity to give her bottom a particularly firm squeeze. He tried hard to concentrate on serving her. Even through her teeth on his tongue and the sucking sensation, her hands on him, edging him so wonderfully.

Her moans and whimpers were too much. He could feel himself about to lose it and he desperately rubbed his fingertips hard and fast right against her gspot. With a grin, he was rewarded with a loud cry into his lips as he felt her spasm hard around his digits.

But that was it. He had made her his and now he was going to be hers. His thighs twitched and convulsed as his hot seed spurted out onto his stomach to dribble wetly down her hand and his cock as he felt her leak onto his hand and fingers. He broke free from her lustful kiss to cry out her name to her, letting her know just how good she was. Christ, she was fucking good.. good at everything. Good at making him feel good, making his heart soar, the list went on and on. He panted softly now, itty bitty whimpers escaping his lips, his fingers softly wiggling against her inner walls. She was still leaning and rocking into his hand even after he had just completely fallen apart and grown still. Her little whimpers of ecstasy ringing in his ears.

His body was damp all over from sweat. He was soaked from sweating and his hand was soaked from her cum. He reached up to his mouth, licking his fingers clean of her. My god how could she taste so wonderful? He was spent but pleased. Very pleased. A wide, stupid smile formed on his lips as he drew her down to his lap to fully sit, his arms coming around her to hug her body against his.

Mabel simply gulped hard as she clung to him, feeling their wetness mingle. For some reason even after all that it made her blush and pant again slightly. Her jaw clenched and she pressed him close to her. "Fuck.. Fuck, Dipper.."

He wanted out of his hot, sweaty clothes. He was panting too, his forehead resting in the crook of her neck, breathing on her collar bone. "Mmm, you said it, Mabes.." His voice was thick and hoarse like gravel from all the panting and crying out. Spent from the pleasure he had received.

They both just sat with each other panting quietly in one another's ears. One or the other occasionally letting out a soft breath or hiss of pleasure as the other moved slightly.

After a time Dipper cleared his throat and coughed.

"So about that project, missy." Leaning back, he eyed her critically. The effect didn't work very good though since he still had a big dumb grin on his mouth.

Pushing her damp hair out her eyes, Mabel puffed her cheeks out as she sighed.

"Oh I finished that thing yesterday."

Dipper's mouth fell open.

"WHAT?! Mabel.. So you knew I was.. like this the whole time? I mean so.. you know… Uh.. Needy.." He whispered the last word but still tried to look annoyed.

Mabel just grinned.

"A girl has to keep her guy on his toes you know?"

Dipper glared at her and gave her neck a raspberry, making her squawk with laughter.


End file.
